Table 3.

Summary table of studies that assessed total salt intake using dietary assessment methods.

Reference	Population	Outcome Measured	Method of Measurement	Results
Charlton et al., 2005 [49]	300 men and women from three different ethnic groups (black, mixed ancestry, and white), aged 20 to 65 y, conveniently sampled from place of work, Cape Town City Council, South Africa. Equal numbers of hypertensive (BP ≥ 140/90 mm Hg and/or on antihypertensive medication) and normotensive (BP < 140/90 mm Hg) men and women were planned (n = 150/group, 50 from each ethnic group).	Dietary intake of Na.	Interviewer administered 3 repeated 24 h recalls. Standard household measuring utensils, rulers, and food photographs of typical South African foods [58] used to quantify food portion sizes. The average daily nutrient intake calculated using Foodfinder III computerized dietary assessment program, based on Medical Research Council Food Composition Tables [59].	In all three subsamples, cereals were the main contributor to total reported dietary Na intake (45.9% to 48.6%), followed by meat and meat products (20.3% to 23.6%) and milk and dairy products (6.3% to 8.1%). In all groups, bread was the major source of dietary Na (25.2% to 40.5%).
Liu et al., 2014 [48]	726 Chinese post-menopausal women who attended a screening visit for a randomized controlled trial testing the effect of soy products supplementation on BP were conveniently sampled.	Dietary intake of food substances from which Na content was determined.	A 3-day food records questionnaire was used to estimate dietary nutrients intake. Food items were those most frequently consumed based on previous local surveys [60,61]. Subjects received a 30 min training on estimation of food amounts, portion, and utensil sizes. Dietary nutrients were calculated based on the China Food Composition Table and local Na database [62,63]. Total Na intake was calculated by summing the estimates from all contributory food items or groups.	Major sources of non-discretionary salt include soup (21.6%), rice and noodles (13.5%), baked cereals (12.3%), salted/pre-served foods (10.8%), Chinese dim sum (10.2%), and sea foods (10.1%) of the total salt intake.
Zhao et al., 2015 [45]	903 families were conveniently sampled for the study. 2952 participants were recruited from families in urban (Xicheng District) and suburban (Huairou District) Beijing, China. Study families were recruited through public primary and junior high schools. Eligible families were those with a child from the enrolled schools.	Dietary salt intake and sources of salt in the diet.	Questionnaire; a simplified “one-week salt estimation method” was designed to measure each family member’s daily salt intake and determine the sources of salt in the diet. This method estimates salt intake from three sources: household cooking, processed food, and cafeterias or restaurants. The methodology was previously published [64].	Soy sauce, vinegar, other sauces and MSG contributed 47%, 34%, 12%, and 7% to total Na intake. The mean Na intake was 5360 (SD 3320) mg/day. Adults consumed more Na 6080 (SD 3640) mg/day than children and adolescents 4400 (SD 2480) mg/day and senior citizens 4080 (SD 1920) mg/d.
Health Promotion Board, Singapore, 2011 [65]	Singaporean National Nutrition Survey 2010, comprised 739 subjects aged 18–69 years conveniently sampled.	Na content in selected foods.	Face-to-face interviews were conducted where dietary practices and food frequency questionnaires were administered. Nutrients and various food groups were assessed by comparing the levels of intake with dietary standards including the Recommended Dietary Allowances (RDAs).	Fish balls, fish cakes, breads, and noodles were estimated to contribute 37% of the population’s salt intake. Daily Na intake was 3265 mg/day.
Du et al., 2014 [66]	Secondary data from China Health and Nutrition Survey (1991–2009) comprising 16,869 adults aged 20–60 y were used.	Na intake from foods and condiments.	Three consecutive 24 h dietary recalls in combination with weighing methods. All foods and condiments recorded and measured. Na intake (i.e., Na from all foods and condiments) were based on their compositions in the Chinese food-composition table.	The average soy sauce intake was 6.9 g/d, accounting for 8.5% of total Na intake. The average processed food intake was 244.7 g/d, which represented 20.8% of all food consumed and accounted for 6.8% of total Na intake. The average MSG intake was 1.5 g/d, accounting for 3.4% of total Na intake.
de Moura Souza, 2013 [44]	Nationwide dietary survey. Food consumption of a representative sample of the Brazilian population 10 years of age or older (n = 34,003).	Na content in foods and beverages.	24 h dietary recall using the nutrition data system for Research software version 2008, the Brazilian Food Composition Table [67], and Brazilian studies on regional foods [68].	Foods with high Na densities (>600 mg/100 g) included salty preserved meats (997 mg/100 g), processed meats (974 mg/100 g), cheeses (883 mg/100 g), crackers (832 mg/100 g), sandwiches (800 mg/100 g), pizza (729 mg/100 g), and breads (646 mg/100 g), as well as oils, spreads, sauces, and condiments (804 mg/100 g). Altogether these food groups contributed 25% (811 mg/100 g) of the average daily Na intake. The mean Na intake was 3190 mg/day.
Anderson et al., 2010 [50]	Participants were 4680 women and men aged 40 to 59 years, recruited by stratified random sampling from 17 diverse populations—community-based or workplace-based—in Japan (four samples), People’s Republic of China (three rural samples), the United Kingdom (two samples), the United States (eight samples).	Na intake was calculated by summing estimates from all contributory food sources, including foods and beverages, ingested at home or away from home.	24 h dietary recall. Na content of each food item was determined using the enhanced national food database for each country.	For China, mean Na intake = 3990 ± 1943 mg/person/day; Soy sauce = 256 mg/person/day, mustard, turnip greens, and cabbage = 143 mg/person/day, sodium bicarbonate and sodium carbonate (tenderizers) = 98 mg/person/day, and noodles were 89 mg/person/day. Japan, mean Na intake = 4651 ± 1279 mg/person/day, United Kingdom mean Na intake = 3406 ± 1162mg/person/day, and United States mean Na = 3660 ± 343.1 mg/person/day

Note: 5 g/d salt = 2000 mg Na, 2%% Na ≈ 4 g of total salt intake.